Device for lifting a seagoing construction such as a drilling rig,provided with lifting members running mutually parallel

ABSTRACT

A device for lifting a seagoing construction such as a drilling rig, which device comprises one or more floater bodies, one or more beam-like lifting members supported movably on a floater body and running parallel or practically parallel to each other, wherein the or each lifting member is supported on at least two support points of the floater body, at least one of which is adjustable in height direction, and the end part of the lifting member lying outside the floater body has a pressure point which is in contact with the construction for lifting, this such that the seagoing construction can be easily connected to the end of the lifting member without this construction suffering damage as a result of the sea swell.

[0001] The invention relates to a device for lifting a seagoingconstruction such as a drilling rig, which device comprises two or morefloater bodies located on either side of the seagoing construction, oneor more beam-like lifting members supported movably on a floater bodyand running parallel or practically parallel to each other and supportedon at least two support points of the floater body.

[0002] Different methods for lifting such constructions at sea havealready been proposed, such as described for instance in the U.S. Pat.No. 5,829,919. Use is made herein of two floater bodies on either sideof the construction for lifting, wherein lifting devices are arrangedprojecting along the longitudinal sides thereof. The drawback of such anembodiment is that the constituent components of the lifting means limitthe free movement of the construction for lifting relative to thefloater bodies. It is herein noted that the swell of the sea requires acontinuous compensation of the relative movements of the floater bodiesin relation to the construction to be lifted.

[0003] The invention has for its object to obviate the above stateddrawback and to propose a lifting embodiment which enables an optimalfreedom of movement of the construction for lifting relative to thefloater bodies and which satisfies the requirement of movementcompensation.

[0004] The device according to the invention is distinguished in that inthe case of each lifting member at least one support point is adjustablein vertical and/or horizontal direction, at least the other supportpoint allowing rotation of the beam-like lifting member in a horizontalor vertical plane, and the free end part of the lifting member has apressure point coming into contact with the construction for to belifted.

[0005] As a result of the beam-like lifting members according to theinvention it is possible for the free end part projecting over thelongitudinal side of the floater body to be embodied withoutspace-requiring rods or cylinders, wherein the support pointdisplaceable in vertical and horizontal direction for the beam-likelifting member is situated at a distance from the lifting point, thissuch that the lifting members can move vertically and horizontallyindependently of each other, thereby providing the optimal freedom ofmovement and movement compensation for the construction for lifting.

[0006] The invention further proposes to provide the said vertical andhorizontal movable support point on the floater body with at least onecylinder, preferably a hydraulic cylinder, in order to control thevertical and horizontal displacement of the lifting member.

[0007] The other support point functions here more or less as pivot,wherein according to the invention this support point is preferablysituated on the top side of the beam-like lifting member.

[0008] In another embodiment the one support point provided with twopendulum arms for suspending movably in all directions a lifting memberor a pair of lifting members extending parallel adjacently of eachother.

[0009] It is herein possible to embody the pendulum arms themselves ascylinders or to suspend the pendulum arms from a separate pivot armwhich is supported by an associated cylinder.

[0010] The invention will be further elucidated in the figuredescription hereinbelow of a number of embodiments.

[0011] In the drawing:

[0012]FIG. 1 shows an upright side view of a seagoing construction, herea drilling rig, along which a prior art device for lifting the upperpart of the construction is shown,

[0013]FIGS. 2 and 3 show respectively a top and side view of a firstembodiment of the device according to the invention,

[0014]FIG. 4 shows a side view corresponding with FIG. 1 of a secondembodiment of the device according to the invention,

[0015]FIGS. 5 and 6 show respectively a top and an upright side view ofa third embodiment according to the invention,

[0016]FIG. 7 is a perspective view of the lifting side of the device ofFIG. 6.

[0017] Referring to FIG. 1, this shows the prior art wherein the liftingdevice is arranged on either side of a drilling rig, which consists of ajacket J and a superstructure B placed thereon, which superstructure Bmust be lifted and then removed.

[0018] For this purpose a separation is arranged in the vertical posts Cat the top side in the jacket once the superstructure B is supported bythe prior art device. This consists of floater bodies 1 for placing oneither side of the jacket, a carriage construction 2 which is arrangeddisplaceably relative to floater bodies 1 and on the side of whichdirected toward the jacket is arranged a lifting device 4 provided withpendulum arms 5.

[0019] It will be apparent that this construction is in the structure ofthe jacket, whereby the relative freedom of movement of floater bodies1, carriage construction 2 and the jacket is obstructed.

[0020]FIGS. 2 and 3 show an embodiment wherein a pair of beam-likelifting members 10 are arranged in mutually parallel direction on eachof the floater bodies 1.

[0021] The number of pairs of beam-like lifting members 10 is forinstance four per floater body, this number depending on the number ofvertical posts C of the jacket.

[0022] Each beam-like lifting member 10 is supported by floater body 1at the one support point 11 respectively the other support point 12. Theend of each beam-like lifting member 10 projecting outside floater body1 is provided with a pressure point 13 which is arranged under a cam Nof a sleeve M arranged round the post C of the jacket, see FIG. 7.

[0023] In the embodiment of FIG. 2 and 3 the one support point isprovided with a hydraulic cylinder 14 for the vertical movement ofsupport point 11 in upward respectively downward direction. Saidcylinder is arranged pivotably to said floating member 1 and beam-likemember in order to allow horizontal displacement in a horizontal planeto said support point. The other support point 12 is provided with apull rod 15 which is mounted pivotally on both the floater body 1 andthe beam-like lifting member. A hydraulic cylinder 16 is arrangedeffecting or controlling a horizontal displacement of lifting member 10,while in top view a third cylinder 17 is placed to bring about orcontrol the lateral freedom of movement of the lifting member. Pressurepoint 13 is thus movable in a three-way coordinate system, with respectto the floating member.

[0024] Because each beam-like lifting member 10 can be adjustedindividually, a high degree of freedom of movement and co-displacementwith the swell of the sea is possible.

[0025]FIG. 4 shows an embodiment wherein the beam-like lifting member 10is supported slidably at the one support point 11 on a cross beam 20which is itself supported on more than one vertically operating cylinder14 for the vertical adjustment thereof.

[0026] The other support point 12 is embodied with a trestle 21 againstwhich the top side of beam-like lifting member 10 supports such that alongitudinal movement, a rotation in a vertical or horizontal plane ofsaid lifting member 10 remains possible.

[0027] In the embodiment of FIGS. 5 and 6 two beam-like lifting members10 are supported in each case at the one support point 11 by a commonhorizontal beam 20 which is suspended from pendulum arms 25 such thatthey can pivot in all directions along the three spatial main axes X, Yand Z, see FIG. 7. Pendulum arms 25 are themselves suspended forpivoting in all directions on a pivot arm construction 26, whereinbetween the housing-like construction 27 arranged on floater body 1 andpendulum arms 25 there is placed a cylinder 28 to enable movement invertical direction of pendulum arms 25, and thereby of beam-like liftingmembers 10. The other support point for beam-like lifting members 10 isarranged in the housing-like part 27 and can be realized in the manneras shown in FIG. 4 respectively FIG. 2.

[0028] It will be apparent from the foregoing that each of the pressurepoints 13 of lifting members 10 has a freedom of movement in alldirections which are largely independent of each other. It is therebypossible to raise the superstructure of a drilling rig under very safeconditions, irrespective of the swell of the sea. The invention is notlimited to the above described embodiment.

1. Device for lifting a seagoing construction such as a drilling rig, which device comprises two or more floater bodies located on either side of the seagoing construction, one or more beam-like lifting members supported movably on a floater body and running parallel or practically parallel to each other and supported on at least two support points of the floater body, characterized in that in the case of each lifting member at least one support point is adjustable in vertical and/or horizontal direction, at least the other support point allowing rotation of the beam-like lifting member in a horizontal or vertical plane, and the free end part of the lifting member has a pressure point coming into contact with the construction for to be lifted.
 2. Device as claimed in claim 1, characterized in that the one support point of the floater body located close to the construction for lifting is provided with at least one cylinder, preferably a hydraulic cylinder, for vertical displacement of the lifting member.
 3. Device as claimed in claim 2, characterized in that a group of lifting members of a floater body is supported by a common cross beam on which the or each cylinder engages.
 4. Device as claimed in claim 3, characterized in that at least the other support point allows a longitudinal displacement and rotation of the beam-like lifting member in a horizontal or vertical plane of the beam-like lifting member.
 5. Device as claimed in claim 4, characterized in that the other support point is arranged on the top side of the beam-like lifting member.
 6. Device as claimed in claim 2, characterized in that the one support point is provided with two pendulum arms for suspending movably in all directions the lifting member or a pair of lifting members extending parallel adjacently of each other.
 7. Device as claimed in claim 6, characterized in that the or each pendulum arm is suspended from a pivot arm, which pivot arm is adjustable in the vertical plane by means of the cylinder. 